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1、第31卷第7期地質(zhì)通報Vo1.31.NO.72012年7月GEoLoGICALBULLETINoFCHINAju1.,2012西秦嶺徽縣一成縣早白堊世盆地沉積特征及其構(gòu)造意義張英利1王宗起,閆臻ZHANGYing—li,WANGZong—qi,YANZhen21.中國地質(zhì)科學(xué)院礦產(chǎn)資源研究所,北京100037;2.中國地質(zhì)科學(xué)院地質(zhì)研究所。北京1000371.InstituteofMineralResources,ChineseAcademyofGeologicalSciences,Beijing10003~
2、Chino;2.InstituteofGeology,ChineseAcademyofGeologicalSciences,Beqing10oo37,China摘要:徽縣一成縣(徽成)盆地是西秦嶺造山帶內(nèi)一個具有代表性的早白堊世走滑拉分盆地。沉積相分析結(jié)果顯示,盆地內(nèi)部發(fā)育不同的沉積相組合.且呈現(xiàn)明顯的時空變化特征。盆地充填序列分析表明,徽成盆地的沉積演化可劃分為4個階段:田家壩組沉積時期、周家灣組沉積時期、雞山組沉積早期和雞山組沉積晚期。田家壩組沉積時期,盆地南部以沖積扇礫巖和辮狀河砂、礫巖沉積組合為主;周
3、家灣組沉積時期,盆地西部以沖積扇礫巖和辮狀河砂、礫巖沉積組合為主;雞山組沉積時期,盆地北部和南部以沖積扇礫巖和辮狀河砂、礫巖沉積為主。在整個沉積過程中,盆地中心表現(xiàn)為湖泊(前三角洲)相細(xì)粒沉積,而河流和三角洲體系則分布于沖積扇和深水湖泊(前三角洲)沉積之間。古流向和物源恢復(fù)結(jié)果證明,盆地沉積物主體來自于盆地北部、南部的花崗巖和前侏羅紀(jì)地層。盆地構(gòu)造沉降和沉積充填過程主要受控于盆地北緣徽鳳斷裂,盆地南部抬升與盆地邊界斷層的活動密切相關(guān),是盆地的主要物源區(qū)。關(guān)鍵詞:徽成盆地;西秦嶺造山帶;早白堊世;沉積特征中圖分
4、類號:P534.53文獻(xiàn)標(biāo)志碼:A文章編號:1671—2552(2012)07—1142-13ZhangYL,WangZQ,YanZ.DepositionalcharacteristicsofEarlyCretaceousHnixian-ChengxianbasininwesternQin-lingMountainsandtheirstructuralsignificance.GeologicalBulletinofChina,2012,31(7):1142—1154Abstract:TheHuixian—C
5、hengxian(Huicheng)basinisawell—preservedpull一叩artbasininthewesternQinlingorogemcbelt.Thereexistvariousdepositionalsedimentaryhthofaciesthatshowobviousspatialvariations.ThesedimentaryevolutionofHuichengbasincanbedividedintofourstages.Thefirststagewascharacte
6、rizedbyminorsedimentsofTianjiabaFormation,andthesecondstagebybasinexpansionofZhoujiawanFormation;thethirdstageofearlyJishanFormationwasam~ximumbasinandthef0urthstagehad~amresofsedimentaryinfilling.InthesedimentaryperiodofTianjiabaFormation,alluvialfanandbra
7、idedriverdominatedproximalareasofthesouthernbasinmargins;inthesedimentaryperiodofZhoujiawanFormation,coarse—gr~nedsedimentsdominatedthewesternbasinmargin;andinthesedimentaryperiodofearlyJishanFormation,alluvialfanandbr~dedriverdominatedproximalareasofthesou
8、thernandnorthernbasinmargins.Fine—gr~nedlacustrine(prodelta)sedimentswereprevalentinthebasincenter.Themiddlebasinwasmosdyfluvialanddeltasandstoneandconglomeratefaciesassociations.Sedimentsweren1ain1vde